- cis-Fused bicyclic sugar thiocarbamates. Reactivity towards amines
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1,2-cis-Fused bicyclic sugar thiocarbamates of gluco and manno configurations have been prepared by treatment of the corresponding O-unprotected amino sugars and glycopyranosyl amines with thiophosgene. The reactivity of these compounds towards amines has been studied in order to determine whether these compounds could act as latent isothiocyanates; it is shown that 1,2-cis-fused bicyclic sugar thiocarbamates are more stable than their trans analogues, and are not transformed into thioureas upon treatment with amines. An unprecedented isomerization of a peracetylated glucopyranoso[2,1-d]oxazolidine-2-thione into a glucopyranoso[2,1-d]thiazolidin-2-one in DMF is also reported. The structure of this thiazolidin-2-one was confirmed by X-ray crystallography.
- López, óscar,Zafra, Encarnación,Maya, Inés,Fuentes, José,Diánez, Ma Jesús,Estrada, Ma Dolores,Pérez-Garrido, Simeón,Fernández-Bola?os, José G.
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- Systematic Structural Characterization of Chitooligosaccharides Enabled by Automated Glycan Assembly
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Chitin, a polymer composed of β(1–4)-linked N-acetyl-glucosamine monomers, and its partially deacetylated analogue chitosan, are abundant biopolymers with outstanding mechanical as well as elastic properties. Their degradation products, chitooligosacchari
- Bordoni, Vittorio,Chaube, Manishkumar A.,Delbianco, Martina,Fittolani, Giulio,Grafmüller, Andrea,Seeberger, Peter H.,Tyrikos-Ergas, Theodore
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p. 2321 - 2325
(2021/01/18)
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- New synthesis of glycolipid immunostimulants RC-529 and CRX-524
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An efficient and scalable synthesis of the potent vaccine adjuvant RC-529 (3) and TLR4 agonist CRX-524 (4) is described in eight steps from 1,3,4,6-tetra-O-acetyl-2-amino-2-benzyloxycarbonyl-2-deoxy-β-d- glucopyranose (10c) in ca. 25% overall yield. The synthesis features the strategic use of the N-Cbz group for β-glycosylation and the selective N,N,O-triacylation of common advanced intermediate 15 with (R)-3- tetradecanoyloxy or decanoyloxytetradecanoic acid (8, 9) late in the synthesis. A new method for preparing and enhancing the enantiopurity of (R)-3-hydroxytetradecanoic acid (6), a key component of 3 and 4 as well as bacterial lipid A, is also described.
- Bazin, Hélène G.,Bess, Laura S.,Livesay, Mark T.,Ryter, Kendal T.,Johnson, Craig L.,Arnold, Jeffrey S.,Johnson, David A.
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p. 2087 - 2092
(2007/10/03)
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- Synthesis of sugar isocyanates and their application to the formation of ureido-linked disaccharides
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The present work describes a facile and practical route to carbohydrate-based isocyanates, a reactive and appealing family of chiral heterocumulenes, wich can be easily converted into disaccharides and pseudodisaccharides interconnected by urea moieties.
- Avalos, Martin,Babiano, Reyes,Cintas, Pedro,Hursthouse, Michael B.,Jimenez, Jose L.,Light, Mark E.,Palacios, Juan C.,Perez, Esther M. S.
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p. 657 - 671
(2007/10/03)
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- The use of N-alkoxycarbonyl derivatives of 2-amino-2-deoxy-D-glucose as donors in glycosylation reactions
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1,3,4,6-Tetra-O-acetyl-2-alkoxycarbonylamino-2-deoxy-β-D-glucopyranoses and 3,4,6-tri-O-acetyl-2-alkoxycarbonylamino-2-deoxy-α-D-glucopyranosyl bromides have been used as donors in glycosylation reactions with model alcohols. β-Glycosides were obtained in good yields and with a high degree of 1,2-trans stereoselectivity.An oxazolidone was formed as the main product from the reaction of some of the glucopyranosylbromides with alcohols of low reactivity, but the formation of all products could be interpreted by a strong participation of the alkoxycarbonylamino group.
- Boullanger, Paul,Jouineau, Martine,Bouammali, Boufelja,Lafont, Dominique,Descotes, Gerard
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p. 151 - 164
(2007/10/02)
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- N-Allyloxycarbonyl derivatives of D-glucosamine as promotors of 1,2-trans-glucosylation in Koenigs-Knorr reactions and in Lewis acid catalysed condensations
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The use of suitably blocked D-glucosamine derivatives possessing the N-allyloxyxarbonyl protective group of the amino function represents potential new routes to 1,2-trans-glucosylations.Both 3,4,6-tri-O-acetyl-2-N-allyloxycarbonyl-2-amino-2-deoxy-α-D-glu
- Boullanger, Paul,Banoub, Joseph,Descotes, Gerard
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p. 1343 - 1348
(2007/10/02)
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- The N-allyloxycarbonyl derivative of D-glucosamine: a potent precursor of β-glycosidation.
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The allyloxycarbonyl protective group of the amino function is a potent precursor of β-D-glucosidation of D-glucosamine and can be selectively removed or preserved in the presence of other usual carbohydrate protective groups.
- Boullanger, P.,Descotes, G.
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p. 2599 - 2602
(2007/10/02)
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